Advances in the modern understanding and control of biological systems have been richly informed by molecular structure information at the scale of interatomic distances. In human health, the impact of molecular biology on dealing with organismic dysfunction, e.g., genetic, metabolic, hematologic, and other disease, is strongly dependent on knowledge of molecular structure. Diffraction studies of single crystals are the most reliable path to authoritative information of this kind. The ultimate aim of this work is to make commercial off-the-shelf (COTS) instrumentation for automated growth of protein single crystals available to every modern molecular biology and biochemistry laboratory. Other kinds of biological macromolecules will be considered at second priority. The crystals produced will be for crystal structure determination in X-ray diffraction and quasi-Laue neutron diffraction experiments. The apparatus will provide for protein crystallization by dynamic thermal control of supersaturation. In its multichamber design, one part will be for discovery of crystallizing conditions, and the other for crystal growth under programmed temperature control. Phase I: apparatus concept will be demonstrated to show merit and feasibility; Phase II: apparatus will be redesigned as necessary and assembled in a prototype; Phase III: preceding work will be converted to COTS instrumentation. PROPOSED COMMERCIAL APPLICATION: Protein crystal structure determination is a key tool of modern biochemistry, biology, and health-related molecular research. Every substantial laboratory in the world has a need for this apparatus, and will buy at least one if it is reasonably priced.